Stroke (CVA) is the leading cause of adult disability in the United States and it is estimated that its prevalence will more than double over the next 50 years. The proposed project address the need for innovative technologies to enhance the function of individuals with disabilities as described in NIH PA-02- 071. Many patients who have sustained strokes are unable to effectively use their hemiparetic lower extremity. Limited mobility in the performance of daily activities adversely affects their quality of life and compromises their independence and overall health status. Rehabilitation techniques engaging the hemiparetic limb in repetitive task practice may improve lower extremity function and quality of life in patients with stroke, but costs limit the number of patients that can utilize this type of therapy. An innovative assistive repetitive motion device using an artificial air muscle has been designed specifically for the rehabilitation of the hemiparetic foot. The objective of this project is to investigate the feasibility of this device. Biomechanical modeling of the lower extremity combined with robotic control algorithms are utilized in microprocessor control of the device. Prototype testing and evaluation will be conducted and a pilot patient evaluation will be completed. This phase I study includes detailed design verification measurements on the device and the collection of pilot data on five stroke patients. The results from this project will provide valuable data as a pre-requisite for submission of a Phase II randomized clinical trial to determine the clinical efficacy of this device in improving the quality of life and function of stroke patients. This project has the potential to increase the availability of effective rehabilitation techniques to patients with stroke.